Semiconductor devices, including Dynamic Random Access Memory devices (DRAMs), utilize storage capacitors to retain data. In the manufacture of DRAMs a polysilicon layer is typically used as the bottom electrode (storage plate electrode) of the cell capacitor. With the density of storage cells packed into today's DRAM devices, a storage plate electrode may require a large surface area to provide sufficient capacitance for data storage and retrieval. In order to gain surface area for the storage plate electrode the polysilicon layer may be deposited using conditions to produce a very rough film, i.e. one with a large surface area.
As evidenced by an article in Applied Physics Letters, Volume 79, Number 3, 16 Jul. 2001, by Ostraat et al., titled: “Synthesis and characterization of aerosol silicon nanocrystal nonvolatile floating-gate memory devices” and by an article in Journal of The Electrochemical Society, by Ostraat et al., 148 (5) G265-G270 (2001), titled: “Ultraclean Two-Stage Aerosol Reactor for Production of Oxide-Passivated Silicon Nanoparticles for Novel Memory Devices,” an aerosol delivery method has been developed to form silicon nanocrystals. The disclosure of each of the forgoing publications is incorporated by reference.
A significant focus of the present invention comprises techniques to form a silicon nanocrystal layer having a significantly enhanced surface area for use in semiconductor devices, such as DRAMs, which will become apparent to those skilled in the art from the following disclosure.